Acid-base status and spiracular control during discontinuous ventilation in grasshoppers

1995 ◽  
Vol 198 (8) ◽  
pp. 1755-1763 ◽  
Author(s):  
J Harrison ◽  
N Hadley ◽  
M Quinlan
Keyword(s):  
Gas Exchange ◽  
Respiratory Physiology ◽  
Acid Base ◽  
Threshold Levels ◽  
Lubber Grasshopper ◽  
Open Phase ◽  
Internal Co2 ◽  
Acid Base Status

Many insects ventilate discontinuously when quiescent, exhibiting prolonged periods during which little or no gas exchange occurs. We investigated the consequences of discontinuous ventilation (DV) on haemolymph acid­base status and tested whether spiracular opening during DV is due to changes in internal gas tensions in the western lubber grasshopper Taeniopoda eques. At 15 °C, resting T. eques exhibited interburst periods of about 40 min. During the interburst period, haemolymph PCO2 rose from 1.8 to 2.26 kPa, with minimal acidification of haemolymph. Animals in atmospheres in which PCO2 was 2 kPa or below continued to exhibit DV, while atmospheres in which PCO2 was 2.9 kPa or above caused cessation of DV. These data indicate that accumulation of internal CO2 to threshold levels between 2 and 2.9 kPa induces spiracular opening in grasshoppers. In contrast to the situation in lepidopteran pupae, variation in atmospheric PO2 had no effect on interburst duration. Relative to lepidopteran pupae, the internal PCO2 of grasshoppers during DV is threefold lower, the PCO2 required for triggering spiracular opening is also threefold lower, and the open phase spiracular conductance is at least tenfold higher, demonstrating that considerable diversity exists in these aspects of insect respiratory physiology.

scholarly journals The physiological challenges of the 1952 Copenhagen poliomyelitis epidemic and a renaissance in clinical respiratory physiology

2005 ◽  
Vol 99 (2) ◽  
pp. 424-432 ◽  
Author(s):  
John B. West
Keyword(s):  
Gas Exchange ◽  
Carbon Dioxide Concentration ◽  
Respiratory Physiology ◽  
Clinical Environment ◽  
Manual Ventilation ◽  
Acid Base ◽  
Ph Measurements ◽  
Applied Physiology ◽  
Acid Base Status ◽  
Disease Hospital

The 1952 Copenhagen poliomyelitis epidemic provided extraordinary challenges in applied physiology. Over 300 patients developed respiratory paralysis within a few weeks, and the ventilator facilities at the infectious disease hospital were completely overwhelmed. The heroic solution was to call upon 200 medical students to provide round-the-clock manual ventilation using a rubber bag attached to a tracheostomy tube. Some patients were ventilated in this way for several weeks. A second challenge was to understand the gas exchange and acid-base status of these patients. At the onset of the epidemic, the only measurement routinely available in the hospital was the carbon dioxide concentration in the blood, and the high values were initially misinterpreted as a mysterious “alkalosis.” However, pH measurements were quickly instituted, the Pco2 was shown to be high, and modern clinical respiratory acid-base physiology was born. Taking a broader view, the problems highlighted by the epidemic underscored the gap between recent advances made by physiologists and their application to the clinical environment. However, the 1950s ushered in a renaissance in clinical respiratory physiology. In 1950 the coverage of respiratory physiology in textbooks was often woefully inadequate, but the decade saw major advances in topics such as mechanics and gas exchange. An important development was the translation of the new knowledge from departments of physiology to the clinical setting. In many respects, this period was therefore the beginning of modern clinical respiratory physiology.

Exercise and forced submergence in the pond slider (Trachemys scripta) and softshell turtle (Apalone ferox): influence on bimodal gas exchange, diving behaviour and blood acid-base status

1999 ◽  
Vol 202 (3) ◽  
pp. 267-278 ◽  
Author(s):  
B. Bagatto ◽  
R.P. Henry
Keyword(s):  
Gas Exchange ◽  
Metabolic Stress ◽  
Respiratory Acidosis ◽  
Diving Behaviour ◽  
Trachemys Scripta ◽  
Acid Base ◽  
Aerial Respiration ◽  
Acid Base Status ◽  
Softshell Turtle ◽  
Apalone Ferox

The dynamics of bimodal respiration, diving behaviour and blood acid-base status in the softshell turtle Trachemys scripta and the pond slider Apalone ferox were investigated at rest and under conditions of stress induced by exercise and forced submergence. During periods of forced submergence, only A. ferox doubled its aquatic gas exchange rate. Both A. ferox and T. scripta increased their aerial gas exchange profoundly following exercise and forced submergence, a pattern indicative of increased anaerobic respiration. Emersion duration increased significantly in A. ferox following forced submergence, and mean apnoeic time decreased significantly in A. ferox following exercise, indicating that a larger proportion of time at the surface was spent ventilating. Also, A. ferox maintained a one-breath breathing bout regardless of treatment. Submergence produced a respiratory acidosis in the plasma of approximately 0.2 pH units in magnitude in T. scripta and a mixed respiratory/metabolic acidosis of 0.4 pH units in A. ferox. Exercise induced an acidosis of 0.2 pH units of primarily metabolic origin in both species. Intra-erythrocyte pH was also reduced in both species in response to submergence and exercise. Both intracellular and extracellular acidoses were more severe and longer lasting in A. ferox after each treatment. Plasma [HCO3-] decreased by 25 % in both species following exercise, but only in A. ferox following submergence. Plasma lactate concentrations increased by equal amounts in each species following exercise; however, they returned to resting concentrations sooner in T. scripta than in A. ferox. A. ferox had significantly higher lactate levels than T. scripta following forced submergence as well as a slower recovery time. A. ferox, which is normally a good bimodal gas exchanger at rest, utilizes aerial respiration to a greater extent when under respiratory and/or metabolic stress. T. scripta, although almost entirely dependent on aerial respiration, is physiologically better able to deal with the respiratory and metabolic stresses associated with both forced submergence and exercise.

A new experimental approach for the study of cardiopulmonary physiology during early development

1988 ◽  
Vol 65 (3) ◽  
pp. 1436-1443 ◽  
Author(s):  
M. R. Wolfson ◽  
N. Tran ◽  
V. K. Bhutani ◽  
T. H. Shaffer
Keyword(s):  
Gas Exchange ◽  
Gestational Age ◽  
Experimental Approach ◽  
Ventilation System ◽  
Lung Compliance ◽  
Pulmonary Gas Exchange ◽  
Acid Base ◽  
Liquid Ventilation ◽  
Age Related ◽  
Acid Base Status

In this report, an experimental approach and newly designed apparatus for liquid ventilation of preterm animals are described. Findings of age-related changes in cardiopulmonary function of this animal preparation are presented. Thirty-one lambs, 102-137 days gestation (term 147 +/- 3 days), were studied. The carotid artery, jugular vein, and trachea of the exteriorized fetus were cannulated under local anesthesia. Immediately after cesarean section delivery, ventilation commenced; warmed (39 degrees C) and oxygenated (PIO2 greater than 500 Torr) liquid fluorocarbon (RIMAR 101) was delivered to the lung by a mechanically assisted liquid ventilation system. Skeletal muscle paralysis, low-dose exogenous buffering, and thermal support were maintained during the 3-h experiment. Pulmonary gas exchange, acid-base status, and cardiopulmonary and metabolic function were assessed. By utilizing these techniques, effective arterial oxygenation, CO2 elimination, acid-base status, and cardiovascular stability were supported independent of gestational age. The results demonstrate a developmental increase in specific lung compliance and mean arterial pressure and decrease in heart rate and systemic O2 consumption per kilogram with advancing gestational age. These findings demonstrate that liquid ventilation negates the dependency of effective pulmonary gas exchange on surfactant development, thereby extending the limits of viability of the immature extrauterine lamb. As such this new experimental approach is useful for the study of physiological development over an age range previously limited to fetal animal preparations and, therefore, may provide insight regarding adaptation of the premature to the extrauterine environment.

Gas exchange, blood gases and acid-base status in the chick before, during and after hatching

1983 ◽  
Vol 53 (2) ◽  
pp. 173-185 ◽  
Author(s):  
H. Tazawa ◽  
A.H.J. Visschedijk ◽  
J. Wittmann ◽  
J. Piiper
Keyword(s):  
Gas Exchange ◽  
Blood Gases ◽  
Acid Base ◽  
Acid Base Status

scholarly journals Recovery from Anaerobiosis in the Intertidal Worm Sipunculus Nudus: II. Gas Exchange and Changes in the Intra- and Extracellular Acid-Base Status

1986 ◽  
Vol 122 (1) ◽  
pp. 51-64
Author(s):  
H. O. PÖRTNER ◽  
S. VOGELER ◽  
M. K. GRIESHABER
Keyword(s):  
Gas Exchange ◽  
Metabolic Rate ◽  
Time Course ◽  
The Body ◽  
Coelomic Fluid ◽  
Acid Base ◽  
Extracellular Acidosis ◽  
Sipunculus Nudus ◽  
Acid Base Status ◽  
Negative Base

Intra- and extracellular acid-base status and changes of coelomic PCOCO2 were investigated during recovery following 24 h of anaerobiosis in Sipunculus nudus L. Metabolism, gas exchange and acid-base status were compared in animals collected during March and October. Anaerobiosis led to an uncompensated metabolic acidosis, the degree of the acidosis depending on the metabolic rate of the animals. During initial recovery in March animals, the acidosis was transiently aggravated in the extracellular, but not in the intracellular, compartment, indicating an efficient regulation of intracellular pH as soon as oxygen was available in the coelomic fluid. The extracellular acidosis was predominantly of non-respiratory origin. The non-respiratory part of the acidosis is attributed to the repletion of the phospho-l-arginine pool. The proton yield calculated from phosphagen resynthesis was highly correlated in time and in quantity to the observed negative base excess in the extracellular compartment. In October animals, strombine accumulation may have contributed to the acidosis that develops during recovery. The amount of succinate, propionate, and acetate in the coelomic plasma had already decreased when the acidosis developed. This discrepancy supports the conclusion that protons move between the body compartments independent of the distribution of anionic metabolites. The respiratory part of the acidosis is attributed to the repayment of an oxygen debt. The increase of PCOCO2 is higher in October than in March animals, probably because of differences in metabolic rate The time course of acid-base disturbances and their compensation is discussed in relation to the time course of metabolic events during recovery and to the priorities of the different processes observed.

Acid-Base Status and Gas Exchange in the Anaesthetized Dog Breathing Pure Oxygen

Respiration ◽  
1972 ◽  
Vol 29 (4) ◽  
pp. 305-316 ◽  
Author(s):  
K.B. Saunders ◽  
D.M. Band ◽  
P. Ebden ◽  
J.P. Van der Hoff ◽  
D.J. Maberley ◽  
...  
Keyword(s):  
Gas Exchange ◽  
Pure Oxygen ◽  
Acid Base ◽  
Acid Base Status ◽  
Anaesthetized Dog

scholarly journals Pulmonary gas exchange and acid–base status during immobilisation of black rhinoceroses (Diceros bicornis) in Zimbabwe

2016 ◽  
Vol 87 (1) ◽  
Author(s):  
Åsa Fahlman ◽  
Anna Edner ◽  
Sandra Wenger ◽  
Chris Foggin ◽  
Görel Nyman
Keyword(s):  
Gas Exchange ◽  
Pulse Oximetry ◽  
Pulmonary Gas Exchange ◽  
Arterial Oxygenation ◽  
Acid Base ◽  
Black Rhinoceros ◽  
Diceros Bicornis ◽  
Arterial Blood ◽  
Acid Base Status ◽  
Free Ranging

When immobilising wildlife, adverse side effects can include hypoxaemia, acidosis and hypertension. Pulmonary gas exchange and acid–base status were evaluated during immobilisation of 25 free-ranging and one boma-held black rhinoceros (Diceros bicornis) in Zimbabwe. The effect of different body positions on arterial oxygenation was evaluated. A combination of the following drugs was used: an opioid (etorphine or thiafentanil), azaperone and an a2 -adrenoceptor agonist (detomidine or xylazine). Respiratory and heart rates, rectal temperature and pulse oximetry–derived haemoglobin oxygen saturation were recorded. Serial arterial blood samples were analysed immediately in the field. Marked hypoxaemia and hypercapnia were recorded in immobilised free-ranging black rhinoceroses. Arterial oxygenation was higher during sternal compared to lateral recumbency. Most rhinoceroses developed acidaemia of respiratory and metabolic origin. Initially high lactate concentrations in free-ranging rhinoceroses decreased during immobilisation. Pulse oximetry was unreliable in the detection of hypoxaemia. Positioning in sternal recumbency and routine use of oxygen supplementation are recommended in the management of immobilised rhinoceroses as measures to improve arterial oxygenation.

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